2 Answers
2

At first sight they don't seem to be "clones" of each other, like it happened with the Nethack wiki vs the Nethack wikia, so there's no need for us to decide what's the canonical source of information. Just choose the reference that you find more accurate, or complete, or up to date as you normally would.

I'll point out that, while Wikia may have bad rap with its aggressive advertisement schemes, it does have a free content license, unlike Curse's Terraria (and Minecraft) Wiki:

You agree to not engage in the use, copying, or distribution of any of the Content other than expressly permitted herein, including any use, copying, or distribution of User Submissions of third parties obtained through the Websites for any commercial purposes. If you download or print a copy of the Content for personal use, you must retain all copyright, trademark and other proprietary notices contained therein.

I suggest we encourage use of the official wiki for two primary reasons:

The official wiki is the
authoritative choice.

The official wiki is more accurate.

Additionally, there's a couple other things to consider:

many of the articles and linked videos are simply copy+pasted from one site to the other (though I have no idea which site originated them), and are mostly identical.

People don't know about the official wiki, perhaps because the wikia wiki shows up first in google searches.

Given the choice between any official source and any unofficial source, I think that we should cite the official source in any given answer. Obviously, if the official source is lacking (such as the official Global Agenda wiki) it makes less sense to cite it, but given two approximately equal sources (as in this case) I am in favor of favoring the officially endorsed source.

I always try to use the official Terraria wiki. Sometimes, however, it is lacking and I use the wikia instead. Such was the case in the question about sharing Terraria worlds. At the time, the official wiki still talked about running two instances of the game (the 1.02 method) so I used the wikia article about the server console.
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user9983Jun 14 '11 at 3:55